A variety of air freshening forms exist in the marketplace that offer the consumer an array of performance options. Such air freshening foil is include aerosols, gels, energy driven units, porous carriers, and membrane devices.
Aerosol sprays offer immediate fragrance awareness upon activation, but dissipate quickly over time. In addition, aerosol sprays represent a costly method of fragrance delivery once the expenses associated with the aerosol container, valve, propellant, and formula, and the manufacturing costs, are taken into consideration.
Water-based gels have traditionally represented one of the least expensive cost options for fragrance delivery due to the large concentration of water in these formulas and formulations. However, a fragrance dispersed in an aqueous gel and thickened with a hydrocolloid generally results in large sized units with a typically short functional life of about 2-3 weeks. Gels are frequently marketed in sizes ranging from 150 grams to 250 grams where the co-evaporation of water with fragrance results in a shrunken residue that is considered highly unattractive.
Power-assisted units, whether they are based on the use of heat, a fan, or both to assist in fragrance dispersion, have been proposed. The energy assisted fragrance dispersion contributes to a greater fragrance awareness. However, such units come at an economic cost that makes these units expensive to manufacture and operate.
Porous carriers are described in U.S. Pat. No. 7,926,735 to Mobley et al. In Mobley, the porous carrier, such as a paperboard card, is impregnated with a fragrance compound for diffusion. However, when fragrance is absorbed directly onto a substrate such as paper, the fragrance release is inordinately high when the paper is newly exposed and subsequently drops dramatically as time passes.
Membrane devices have become appreciated for their lightweight construction and generally smaller size. Membrane devices typically are constructed with a release membrane covering the full expanse of a shallow tray, which contains the fluid contents to be dispensed. Such membrane devices, however, offer no platform for graphic design applications. Therefore, it is necessary to utilize a separate housing to contain the membrane cartridge. Such housing may enable a surface for design.
U.S. Pat. No. 4,145,001, to Weyenberg et al., describes a package having an absorbent pad located under a permeable layer that is uniformly but weakly bonded to an upper barrier layer. In order to activate the package of Weyenberg, a user completely removes the upper barrier layer from the permeable layer. However, the complete removal of the upper barrier layer does not allow the package to provide a visual or decorative enhancement when in use. Moreover, because the entire upper barrier is removed to expose the entire permeable layer to the ambient air, the options for adjusting the delivery rate are limited. For a given fragrance composition and package material, the delivery rate for the package of Weyenberg can be adjusted only by changing the thickness of the permeable layer or changing the size of the package. However, each of these options would require modifications to the manufacturing machinery such as the permeable layer forming machinery.
There remains a need in the art to provide a small-sized, easily deployed, and disposable membrane air freshener, which has design potential, is economical to fabricate, and which will provide a pleasing fragrance experience over the functional life of the device.